Clinicopathological significance of sulfite oxidase expression in surgically resected lung adenocarcinoma

Aim: The coenzyme sulfite oxidase (SUOX), located in mitochondria, plays a role in redox and metabolism. Its expression has been associated with cancer progression and prognosis. Lung cancer has a high incidence rate and poor prognosis. We aim to clarify its expression in lung adenocarcinomas and investigated the utility of SUOX expression as a recurrence factor in operable lung adenocarcinoma.

Methods: We used 60 formalin-fixed paraffin-embedded samples of operable primary lung adenocarcinoma between 2017 and 2018 to immunohistochemically assess SUOX expression levels. Patients were classified into a high or low SUOX expression group, and the associations of SUOX expression with clinicopathological findings and recurrence were analyzed.

Results: We revealed that high SUOX expression was significantly (p < 0.05) associated with sex, low Brinkman index, histological type, histological grade and positive for epidermal growth factor receptor (EGFR) mutation. High SUOX expression (HR = 10.218, 95% CI 1.758‒59.376, p = 0.0096) and pathological Stage (HR = 7.538, 95% CI 1.95‒29.14, p = 0.0034) were independently associated with relapse free survival.

Conclusion: High SUOX expression may be a new indicator of recurrence risk in surgically resected lung adenocarcinomas.